Directed path graphs

The concept of a line digraph is generalized to that of a directed path graph. The directed path graph of a digraph D is obtained by representing the directed paths on k vertices of D by vertices. Two vertices are joined by an arc whenever the corresponding directed paths in D form a directed path on k + 1 vertices or form a directed cycle on k vertices in D. Several properties of are studied, in particular with respect to isomorphism and traversability.